This is not meant to be used as system PropertyEditor but rather
as locale-specific date editor within custom controller code,
parsing user-entered number strings into Date properties of beans
and rendering them in the UI form.

In web MVC code, this editor will typically be registered with
binder.registerCustomEditor calls in a custom
initBinder method.

CustomDateEditor

Create a new CustomDateEditor instance, using the given DateFormat
for parsing and rendering.

The "allowEmpty" parameter states if an empty String should
be allowed for parsing, i.e. get interpreted as null value.
Otherwise, an IllegalArgumentException gets thrown in that case.

The "exactDateLength" parameter states that IllegalArgumentException gets
thrown if the String does not exactly match the length specified. This is useful
because SimpleDateFormat does not enforce strict parsing of the year part,
not even with setLenient(false). Without an "exactDateLength"
specified, the "01/01/05" would get parsed to "01/01/0005". However, even
with an "exactDateLength" specified, prepended zeros in the day or month
part may still allow for a shorter year part, so consider this as just
one more assertion that gets you closer to the intended date format.